Is it better to use require_once('filename.php') or require_once 'filename.php';

Question

Is this just a stylistic difference, or does using require_once(\'filename.php\') vs require_once \'filename.php\' have actual load/efficiency diff

Answer 1

include, include_once, require and require_once are not functions, they are statements, that is why you should not use ().

Also, consider this from php.net: